This invention relates to mechanism for securely retaining sockets or other tool attachments on, and easily releasing them from, socket wrenches and other torque-transmitting tools, and is particularly adapted for use with extension bars of the type now commonly used with wrenches. The mechanism of this invention can generally be used on all hand-held tools, including power and impact tools having removable sockets or other tool attachments and in particular can be used with hand-held socket wrenches including ratchet wrenches.
This application is a continuation in part of applicant's co-pending application Ser. No. 06/362,769, filed Mar. 29, 1982 and entitled "Quick Release and Automatic Positive Locking Mechanism for Socket Wrenches and Extension Bars for Socket Wrenches."
Whereas this invention may be employed with various types of wrenches or other torque tools, in its application to wrenches it is especially adapted for use on wrenches and tools that have drive studs at least slightly longer than the drive studs conventionally employed on ratchet wrenches. This invention is also particularly well suited for use on extension bars of the type now frequently employed to transmit torque to attachments for socket wrenches for reaching work located in remote or otherwise inaccessible places, thus making the socket wrench a more versatile tool.
Socket wrenches of the type referred to herein have a handle, a head or other torque transmitting portion, and a square, hexagonal or like drive stud for receiving removable sockets or other tool attachments.
For many years prior to the invention of a quick-release mechanism for socket wrenches (first disclosed in U.S. Pat. No. 3,208,318, Roberts), removable sockets were usually secured to the wrench by a conventional ball detent device which in use necessitated that the sockets be manually pushed onto and pulled off of the drive stud of the wrench against the resistance of the ball detent.
In the conventional ball detent design, the ball detent is spring mounted in an aperture in the drive stud with the normal position of the ball detent being in an outward position, that is, with the ball projecting outward of the surface of the drive stud. When the socket is mounted on the drive stud, the spring loaded detent protrudes from the exterior surface of the drive stud to engage a recess in the socket and thereby hold the socket onto the drive stud. To remove the socket from this conventional ball detent design stud, the user normally grasps the socket with one hand and exerts a pulling force on it while firmly holding the wrench against said pulling force with his other hand, thereby forcing the spring loaded ball detent to recede into the aperture so that the socket can be pulled or pried off and thus released from the drive stud.
This conventional manner of securing and releasing sockets, however, resulted in a great many practical difficulties. One of these problems was that the removal of the socket required the use of both of the user's hands: one hand to hold the handle of the wrench and the other hand to pull the socket off the drive stud. Removal of the socket in this manner became a particularly time-consuming and labor wasting task, especially when the socket or the user's hands became greasy and it consequently became difficult for the user to grasp and hold the socket while pulling on it. This problem was exacerbated by the spring necessarily present in a new wrench which had to be quite stiff if the spring was constructed to exert a force sufficient to retain a socket or other attachment through the expected life of the wrench.
Moreover, removal of this socket proved difficult or impossible if the conventional ball detent spring mechanism jammed, as it sometimes did when it became contaminated with dirt or grease, both of which are, of course, ordinarily present in the working places of mechanics who frequently use such tools. The consequence of such contamination was that a great deal of force was ordinarily required to remove the socket.
As a makeshift remedy for these problems, users frequently removed the socket from the wrench by prying it off with a screwdriver or other levering device. Indeed, the problem became so acute that some manufacturers offered special tools to pry off sockets. This time-consuming procedure of removing sockets from wrenches became particularly troublesome for commercial mechanics, who frequently use such wrenches for many hours during the day and change sockets many times during that period.
As indicated above, the first and only fully effective solution to this problem was provided by the "quick-release" mechanism disclosed in the above-identified Roberts patent. As shown in that patent (FIGS. 1, 2, 3, 4), a longitudinal passage in the drive stud receives a slidable pin, one end extending through the top of the head of the wrench and terminating in a control knob and the other end substantially flush during normal operation with the bottom face of the drive stud. The drive stud has an aperture for receiving a ball detent, the edges of the aperture preventing the ball detent from passing outside the stud.
A coil spring mounted in a section of said longitudinal passage maintains the pin normally in a position to keep the ball detent in an outward position, the ball detent thereby normally engaging and securely holding the socket. The slidable elongate pin is provided with a recess, so that when the operating button is depressed, the pin moves longitudinally in the passage until the detent is received in the recess. At that point, the socket is no longer secured to the drive stud and can be permitted to drop off through the force of gravity.
The above-described invention proved to be a remarkable success that was quickly adopted in most conventional socket wrenches and virtually revolutionized the socket wrench field. It enabled for the first time users of socket wrenches to easily and swiftly remove sockets from socket wrenches and replace sockets on the drive stud with little effort, and while using only one hand. One-handed operations were a decided time and cost advantage when, for example, a mechanic needed one hand to change a socket while holding a part he was working on in place with the other hand. Today, a large percentage of all socket wrenches in use are provided with some mechanism to facilitate the release of sockets from wrenches.
Roberts' quick-release mechanism, however, did not provide for positive locking of the socket onto the drive stud to prevent accidental release of the socket. This added feature would be highly useful on many power and impact tools and also on socket wrenches when, for example, work is being done on bridges or high buildings or the like where the accidental loss of a socket by unintended release not only produces the serious problems of replacing the lost socket but also the likelihood of damage to valuable or delicate machinery or property below and even danger to life.
There are numerous other circumstances where a positive locking mechanism would be highly desirable. For example, in using socket wrenches in repetitive tasks requiring prolonged use of the same tool attachment, a positive locking mechanism is highly desirable. In another circumstance, it is sometimes necessary to employ what is referred to as an extension bar to facilitate the removal of bolts that would otherwise not be accessible to a mechanic. An extension bar is ordinarily secured to the drive stud of the wrench, as is any regular socket and at its other end it is provided with a similar drive stud for receiving a socket. Prior to the present invention the sockets were retained on and released from the extension bar drive stud by a conventional ball detent mechanism of the kind described above.
With such detent mechanism a user removed a socket from the extension bar, by simply pulling it off. But in doing so, it was imperative that he not also remove the extension bar from the wrench drive stud, (which would often happen with a conventionally designed ball detent mechanism) as to do so would be frustrating and time consuming, requiring a three-hand operation. The incorporation of a locking mechanism onto the socket wrench to securely lock the extension bar onto the drive stud alleviates this problem. Mechanism for accomplishing such locking of extension bars as well as sockets and other tool attachments is now the subject of this inventor's U.S. Pat. No. 4,420,995, issued Dec. 20, 1983.
Extension bars of the type here referred to are employed when it is necessary to project the socket into an inaccessible area but which can accommodate the extension bar and socket. Such situations are encountered frequently when working on various types of machines that have nuts, bolts or other work pieces closely surrounded by other machine parts or other objects which allow only limited working space such as will accommodate only an extension bar and socket. In such cases an extension bar of suitable length is required which has at its upper end a suitable recess adapted to be attached in driving relation to and be retained on the drive stud of a wrench and at its lower end a drive stud for receiving a socket or other tool attachment.
There is a need therefore, in the field of tools employing extension bars of the type here contemplated, to provide mechanism which is inexpensive, reliable and easily constructed by which sockets and other tool attachments may be easily applied to, firmly retained on and quickly released from the drive stud portion of the extension bars and by which the sockets and other tool attachments may be positively locked in operative association to effectively preclude the possibility of accidental release.
Whereas the invention here disclosed is of such construction that it is particularly well suited for use with extension bars, it is not to be so limited as the same construction can be used with the same functional advantages on wrenches of various sorts which employ sockets or other tool attachments, including for example ratchet wrenches, "speeder" wrenches, and "T-bar" wrenches (examples of which are disclosed herein) as well as other types of tools which are capable of embodying the structural features which characterize this invention.